US2294316A - Shoe last - Google Patents

Description

Aug. 25, 1942. c. R. PARKER SHOE LAST Filed Feb. 1, 1940 IN VENTOR. 0/55 752, P. PARA 5Q. m zmm ATTORNEYS.

Patented Aug. 25, 1942 UN [TED STATES ATENT ()FFICE SHOE LAST Application February 1, 1940, Serial No. 316,711

4 Claims.

This invention relates to shoe lasts, and more particularly to improvements in hollow metal lasts for the manufacture of rubber footwear, such as boots and overshoes.

In the process of manufacturing rubber footwear, it is conventional practice to mount a plurality of the lasts upon a conveyor which carries the lasts in a predetermined path for the performance of a desired sequence of operations, such as curing, in the manufacture of the footwear. Hollow metal lasts have been found to be greatly superior to any other type of last for the manufacture of rubber footwear, and in previous use thereof these lasts have been provided at their upper end faces with a pair of holes into which studs or pins carried by the conveyor are adapted to fit for the purpose in holding the last in desired position upon the conveyor during the processing of the footwear being built around the last. These hollow lasts are generally formed of some lightweight material, such as an aluminum or magnesium alloy which is subject to rapid wear, and consequently considerable dlfiiculty has been experienced with lasts formed of these alloys by reason of the fact that the holes therein which receive the pins or studs of the conveyor are enlarged in use with resulting loose fit thereof on the conveyor pin or stud. Hence the lasts may tilt out of operative position on the conveyor.

For purposes of economy, the pins on the conveyor are so arranged that the adjacent sets thereof are spaced apart a distance only slightly greater than the length of the foot portion of the last. Consequently when the fitting of the last on the conveyor pin loosens to permit the last to tilt, the tilting may result in contact of the adjacent lasts. When this is encountered during the process of making the footwear and particularly during the process of curing thereof, the

footwear bears a mark caused by the contact of the partly formed footwear on adjacent lasts so that said footwear is disfigured and unfit for sale as first class merchandise. Consequently considerable loss is possible and likely if the lasts are not firmly held upon their conveyor in proper position.

It is the primary object of my invention to provide a hollow metal last formed of lightweight material, and so constructed and reinforced by the use of hard metal parts as bearing surfaces engaging the conveyor pins, that the interconnection between the last and the pin will be entirely formed of hard metal, and thus be capable of use for an indefinite period without suffering wear 55 metal,

which will permit the lasts to tilt upon the conveyor.

A. further object is to provide a hollow metal last formed of lightweight material having embedded in the upper face thereof a pair of hard metal sleeves in accurately positioned relation for the reception of studs or pins on a conveyor.

A further object is to provide a last formed of lightweight metal with sleeves formed of hard and having knurled exterior surfaces adapted to be embedded and firmly anchored in a wall of the soft metallast.

Other objects will be apparent from the description and appended claims.

In thedrawing:

Fig. l is a longitudinal vertical sectional view of my shoe last illustrating the same mounted upona conveyor, and with one sleeve shown in section and the other in elevation.

Fig.2, is a transverse sectional View taken on line 2'-2 of Fig. 1.

Referring to the drawing, the numeral Ill designates a conveyor, which is here illustrated as constituting a flexible endless chain. The conveyor is provided at spaced points along its length with sets of spaced upwardly extending pins or studs I I, the studs of each set being spaced apart a predetermined dimension and the sets being spaced from each other a predetermined dimension. It will be understood that the conveyor I0 is mounted upon and operated by suitable supporting and operating means (not shown) of such character that the pins or studs I I will always be maintained in vertical or upright position.

My improved last comprises a hollow metal member I2 of any desired shape or form to provide a foot portion I3, heel portion l4, and leg portion 15 of desired size and contour. The upper end of the leg portion l5 has a transverse wall 16 in which an opening 11 is usually provided, said opening I! being formed usually by the arbor mounting the core which shapes the inner surface of the Walls of the last. The opening 11, of course, also facilitates removal of the core material after the last has been cast. The walls of the lasts are of substantially uniform thickness throughout, with the possible exception that the wall It may be slightly thicker than the remaining last walls. In no instance, however, it is customary to provide any wall of the last greatly exceeding A; or inch in thickness.

Within the upper wall [6 I embed in predetermined spaced exactly parallel relation, a pair of sleeves I8 whose outer ends are preferably either flush with or slightly inset from the outer surface of the plate portion l6 of the last. The spacing of these sleeves must be exactly the same from center to center as the spacing of the centers of the studs or pins H. The sleeves I8 may be of a length greater than the thickness of the walls l6 if desired. Whereas the last itself is formed of a soft metal, such as magnesium or aluminum alloy, the sleeves [8 are preferably formed of steel or some other hard and substantially non-wearing material. The exterior faces of the sleeves l8 are preferably knurled throughout their length, as illustrated in Fig. 1, so that the combination of the shrinkage of the non-ferrous lightweight material on the sleeves during the cast operation, together with the anchoring action of knurled outer surface, will solidly embed and secure the sleeves in desired posi- 4 tion. The interior surfaces of the sleeves I!) are preferably smooth.

It will, therefore, be seen from the above description that a solid and substantially nonwearing contact is provided between the last l2 and the pins ll of the conveyor. Additionally by the use of sleeves I8 of a length greater than the thickness of the last wall IS, a greater area and extent of positioning contact is aiforded between the studs H and the last, which assists in maintaining the last in operative position upon the conveyor. In this way the full length of the studs ll may be utilized for accurate positioning of the last upon the conveyor without at the same time requiring any excessive overall thickness of the Wall I6 of the last which would increase amount of the metal required and also the weight of the last.

The problem which is solved by the use of these elongated hard metal sleeves is one of long standing and has been a source of trouble and loss to manufacturers of rubber footwear for many years. In actual tests since use of the hard metal sleeves aforesaid has been begun, it is found that this, the instant construction, fully solves all these difiiculties and eliminates loss by reason of contact between adjacent lasts in the curing or other operations of the footwear While mounted upon the conveyor.

I claim:

1. A shoe last comprising a hollow cast body having a top wall, and a pair of rigid preformed separate metal sleeves fixedly cast in substantially, coplanar parallel relation in said top wall at their outer end portions and terminating within and spaced from said body at their inner end portions.

2. A shoe last comprising a thin-walled hollow cast body, and a pair of preformed open ended sleeves having roughened exterior surfaces and substantially smooth interior surfaces, the top wall of said body being cast around said sleeves to permanently anchor said sleeves .in spaced substantially coplanar parallel relation.

3. A shoe last comprising a hollow cast body of thin wall section, and a pair of rigid preformed sleeves fixedly cast at their outer end portions within the top wall of said body in spaced substantially coplanar and parallel relation, said sleeves being of a length greater than the thickness of said top wall and terminating within and spaced from said body, the inner surface of each sleeve being substantially smooth and at least the imbedded portion of the outer surface being roughened.

4. A shoe last comprising a hollow cast body having configured walls of substantially uniform thickness and a top wall spanning the upper end of said body, and a pair of preformed sleeves of a length greater than the thickness of said configured walls, said top wall being cast around said sleeves to anchor said sleeves in substantially coplanar and parallel relation spaced from each other and from the configured Walls of said body.

CHESTER R. PARKER.

Images